What are the performance differences between collections in C#?

What are the performance differences between collections in C#?

In C#, different collections like List, Dictionary, and HashSet have varying performance characteristics. For example, List<T> offers fast access by index but slow insertions and deletions, while Dictionary<TKey, TValue> provides fast lookups but requires more memory.

Can you explain when to use a List versus a Dictionary?

Use a List when you need ordered elements and frequent access by index. Use a Dictionary when you need fast lookups by key and don't care about the order.

What about the performance of HashSet?

HashSet is great for storing unique elements and offers average O(1) time complexity for add, remove, and contains operations, making it efficient for membership tests.

Are there any scenarios where I should avoid using collections?

Yes, avoid using collections for very large datasets where memory consumption is a concern, or when you need to maintain order and perform frequent insertions and deletions.